Metamorphic layer properties with gradient microstructure distribution of 8Cr4Mo4V steel by grinding

In the grinding process, the metamorphic layer difference from the workpiece material is created on the grinding top surface, and its properties can greatly affect the bearing surface yield strength. In this study, the phase content and grain size distribution of 8Cr4Mo4V with the metamorphic layer were detected using advanced surface observation tools, and the influence of grinding process parameters on the microstructure of the metamorphic layer was considered at the same time. In addition, based on the modeling of the observed metamorphic layer with gradient microstructure distribution, tensile simulations of the metamorphic layer were performed by the crystal plasticity finite element method to investigate the effects of different grain size, phase content, and surface texture strength on its mechanical property like yield strength. Furthermore, the yield strength of the metamorphic layer was characterized by the nanoindentation technique. Finally, it was found that the grinding process parameters affected the microstructure and distribution of the metamorphic layer and thus changed its yield strength, and this study which combines the experiment and simulation aimed to quantitatively analyze the influence of different microstructures on the metamorphic layer.